Error-preventing terminal for dynamos



F. MUNZ. ERROR PREVENTING TERMINAL FOR DYNAMOS. APPLICATION FILED MAY 4, 1920.

Patented Mar. 22, 1921.

PATENT OFFICE.

FRIEDRICH MU'NZ, OF STUT'lG-ART, GERMANY.

ERROR-PREVENTING TERMINAL FOR DYNAMOS.

Specification of Letters Patent.

Patented Mar. 22, 1921.

Application filed May 4, 1920. Serial No. 378,914.

T 0 all whom it may concern:

Be it known that I, Fnrnoiuon Mt'mz, residing at Stuttgart, Germany, have invented certain new and useful Improvements in Error-Preventing Terminals for Dynamos, of which the following is a specification:

The use of accumulators in vehicles illuminated by means of an electric dynamo is unavoidable. But a lighting installation that is supplied with current from a dynamo and accumulators requires skilled attendance because by wrong connections the battery and the dynamo might sustain damage or even be destroyed.

The invention relates to an exchangeable terminal arrangement or connecting device by which wrong connections between the poles of the battery and the dynamo are prevented, even if the connections are carried out by unskilled persons.

This is accomplished by so arranging the connecting device that it is easy to remove and to reverse according to the direction of rotation of the dynamo.

The tapping of the current from the dynamo terminal and the conducting of the current to the place of consumption or to the charging station is preferably carried out by means of a contact pin that may be inserted from either of two opposite sides into a socket mounted in the frame of the connecting device and having two concentric contact pieces, an inner piece and a conentric outer ring. The contact pin is inserted from the one or the other side of the said frame according as the one or the other surface ofthe connecting device is turned outward or to the front. Attached to the casing of the machine is a spring plug which enters the concentric outer contact ring when the connecting device is applied to the dynamo. The spring plug which serves to conduct the current from the outer contact ring to the metallic body of the dynamo or to earth, does not, however, penetrate so far into this ring as to come into touch with the said inner contact piece.

By this means all possibility of connecting to a wrong pole is avoided. The middle contact piece inside in the concentric ring of the socket is used for connecting the dynamo to the battery so that here also all mistakes are prevented.

A constructional form of the invention is shown in the drawing in which-- Figure 1 shows a dynamo having an errorproof terminal arrangement fixed at its commutator end, and a connection between the terminal arrangement and a distributing board, and between the distributing board and a battery of accumulators.

Fig. 2 shows a section through the terminal arrangement with its concentric con tact socket and through the commutator of the dynamo.

Fig. 3 is a horizontal section through the concentric contact socket and the terminal arrangement, and

Fig. 4 is a longitudinal section through a connecting plug that fits into the socket and by which the current is tapped from the dynamo and conducted to the distributing board or battery as shown in Fig. 1.

The plate 11 Fig. 3 of the commutator end of the dynamo has a protuberance or spring plug which fits into the outside ring 7 of the contact socket that is embedded or fixed in the frame of the terminal arrangement or connecting device. The spring plug is electrically connected to the plate and body of the dynamo. Also fixed to the plate 11 but insulated from it is a spring contact pin that is situated lower than the concentric ring 7 on a level with the metallic conductor 4, Fig. 2. The insulating material 8 of the comiecting device has two holes similar to 15 one in either side and the aforementioned insulated contact pin passes through the one or the other of these holes according as the one or the other face of the connecting device abuts against the plate 11,

this depending, of course, on which end of the concentric ring 7 is slipped onto the protuberance Fig. 3 of the plate 11. WVhether the terminal arrangement is slipped over the protuberance and the insulated pin into the position shown in Fig. 2 or into a reversed position in which the brush 2 occupies the position now occupied by brush 1 makes no difference as far as the connection between the insulated pin and the conductor l, and between the concentric ring 7 and the protuberance is concerned.

The carbon brushes 1 and 2 conduct the current from the commutator 8 and it passes through the conducting bars 4 and 5 to the two ring shaped concentric portions 6 and 7 of the contact making socket. The current conducting parts are cast or embedded in a frame of insulating material 8. An arrow 9 is provided on the frame which points in the direction from the one brush to the other and in placing the terminal arrangement in position care must always be taken that the arrow points in thc direction of rotation of the armature. When the terminal arrangement 8 is removed the space 10 is disclosed to View so that the direction of rotation of the armature canbe seen. If'the terminal arrangement 8 isfixed to lthe plate 11 in such a manner that the arrow 9 points in'the direction of rotation of the commutator the central contact or pole .12of the plug that is screwed into the socket 6 will always f be connected toa certain pole, say the negative pole, of the dynamo and the outer or ring contactthat corresponds to? (or .13 or earth Figjll) will always be positive, for a reversal of the direction of rotation will alwaysbe accompanied by a reversal of the position of the brushes 1 and2. Now :in

order to maintain the same polarity in the field winding when the terminal arrange.

ment is reversed the on'eend of this winding is permanently'connected to the iron orbody of the machine while the other end-is-conprojecting from the commutator end of the dynamo, a frame adapted to abut with either of two surfaces against-the said commutator end, an indicator on the frame for showing the directionofrotation of the commutator,

a contact sleeve extending from the one to the other of the said surfaces of the said frame and adapted to have either of its ends slipped onto a said projecting terminal, a contact in the middle of the said sleeve, brush connections arranged in the'said frameand extending from the contact sleeve and the said middle contact, and channels in-either side of the said frame through which'a said projecting.terminalenters into contact with a said brush connection.

' 2. Terminalarrangement for tapping current from a dynamo, comprising a terminal projecting from the dynamo, a frame adapted to abut with either of two surfaces against the dynamo, an indicator on the frame for showing the direction of rotation of the dynamo, a contact socket passingthrough the said frame and adapted to have either rend slipped onto the said projecting terminal, a middle contact inthe said socket out of the reach of the saidprojecting terminal, and brush connections arranged in the said frame and extending from the socket and the middle contact.

In testimony whereof vI aflix my signature in presence of two witnesses. v

FRIEDRICH .MUNZ. Witnesses:

Fume MARX, ELSA SoHoLLHoRN. 

